Search

Here, we introduce the synthesis and deposition of organic/inorganic composite ink on cellulose paper using a rapid ultrasonic spray deposition approach that can be incorporated as a counter electrode (CE) in flexible dye-sensitized solar cells (FDSSCs). The composite ink comprised a copper indium sulfide (CuInS

The development of organometal halide-based perovskite solar cells (PSCs) has made remarkable progress in photovoltaics. The commercialization of PSCs is still significantly limited, owing to their poor stability and the high material cost of a hole transport layer (HTL) and metal electrodes. To counter these issues, a carbon-based HTL and noble metal-free PSCs are being used. In this work, the effect of Cs-doping on perovskite film morphology and device performance has been systematically studied because the Cs+ and Br− ions-doping has proved to be a good choice to improve the stability of PSCs in combination with a carbon electrode. The results showed that when the Cs-doping concentration in perovskite film, MA1−xCsxPb(I1−yBry)3, was equal to x = 0.09, there was a substantial change in the morphological and optoelectronic properties of perovskite films. The grain size of perovskite films was improved from 70 nm (x = 0.00 control) to 170 nm (x = 0.09 Cs-doped), reducing grain boundaries. Moreover, the trap states were additionally passivated resulting in improved radiative recombinations in the perovskite film. The device fabrication was carried out in a controlled dry glovebox, with relative humidity < 40% using carbon as a counter electrode. As a result, Cs-doped PSCs showed a significant increase in efficiency (5.27%) compared to control PSCs (1.55%).

Development of cost effective and easily scalable energy systems for harvesting renewable solar energy is attractive proposal for future. This work presents facile synthesis of ZnO nanostructures with different morphologies simply providing different solvating conditions in a hydrothermal process, for their subsequent use in dye sensitized solar cell (DSSC) device. ZnO nanoprisms were obtained in aqueous solution where addition of methanol/ethanol resulted in formation of hollow nanoprism while methanol in alkaline solution yield ZnO nanorice morphology. The obtained nanostructures were characterized for structural, morphological, elemental, optical and surface area analysis. Then devices were fabricated using the grown nanostructure and tested their response under 1 sun conditions for dye sensitized solar cells with N719 dye-loading. Among different nanostructure morphologies, ZnO nonorice showed superior performance reaching the maximum conversion efficiency. We attribute this to large surface area, better conductivity, and enhanced dye adsorption of nanorice in comparison to other synthesized ZnO nanostructures.

Background: The photocatalytic degradation of toxic organic compounds has received great attention for the past several years. Dyes, such as methyl orange (MO), are one of the major pollutants which create environmental hazards in the hydrosphere, living organisms and human beings. During photocatalytic degradation, NPs are activated in the presence of UV–Vis radiation which in turn creates a redox environment in the system and behaves as a sensitizer for light-induced redox mechanisms. Tin oxide (SnO2) is one of the prominent, but less investigated, nanomaterials compared to titanium oxide (TiO2) and Zinc oxide (ZnO) nanoparticles (NPs). Methods: Herein, Buxus wallichiana (B. wallichiana) leaf extract was utilized as a reducing and capping agent for the biosynthesis of SnO2 NPs. The effects of the calcination temperature on their photocatalytic, structure and surface properties were then examined. The degree of crystallinity and the crystallite size were determined through X-ray diffraction (XRD) analysis. The pore size and surface area were calculated by Burnett–Emmitt–Teller (BET) and Barrett–Joyner–Halenda (BJH) methods based on nitrogen desorption data. Morphological changes were assessed by scanning electron microscopy (SEM). The optical behavior was analyzed through UV–Vis diffuse reflectance spectroscopy (DRS) data and the band gap subsequently calculated. The photocatalytic efficiency of SnO2 NPs was evaluated by double beam UV–Vis spectrophotometry under the influence of initial MO concentration, catalyst dose and pH of MO solution. The surface functional moieties were identified using Fourier transform infrared (FTIR) spectroscopy. All the calcined SnO2 NPs were used as photocatalysts for the mineralization of MO in aqueous media. Results: The degree of crystallinity and the crystallite size increased with the calcination temperature. The transmittance edge obtained for all the calcined SnO2 NPs shows a maximum absorbance in the visible range (λ-max = 464 nm). Moving toward higher wavelengths, a sudden intense red shift (from 464 nm to 500 nm), attributed to the incorporation of a hydroxyl radical at the ortho-position in the benzene ring associated with the dimethylamine group of MO, was observed in the absorbance of the samples calcined up to 300 °C. The percentage degradation of MO was found to decrease with increasing calcination temperatures. The optimal photocatalytic activity toward MO (15 ppm) in a solution of pH = 6 was obtained with 15 mg SnO2 NPs calcined at 100 °C. Conclusions: UV–Vis absorption spectroscopy demonstrates that the absorption spectra of MO are strongly modified by the calcination temperature. This work opens new avenues for the use of SnO2 NPs as photocatalysts against the degradation of industrial effluents enriched with different dyes.

Due to soiling on Photovoltaic modules, the active area reduces causing loss in short circuit current of the device due to lower light transmittance. Soiling on Photovoltaic modules depends upon environmental factors like wind, humidity, dust composition, tilt angle, orientation, and material of the module. Soiling loss studies conducted in outdoor conditions are unreliable as environmental factors are uncontrolled and vary with time hence there is a need to explore an indoor soiling station having controlled environment and stimulated conditions. This study reports an indoor soiling station with controlled environment capable to simulate the daily outdoor soil cycle in few hours. The designed soiling station is featured with cost reduction, design improvements, and automation that has been designed to simulate the soiling effects to study the effects of environmental parameters under desired and controlled conditions. The proposed soiling station is capable to explore optimized soiling loss effects on Photovoltaic modules by varying tilt angle, humidity, wind speed, and temperature. The soiling uniformity in the soiling chamber was confirmed by using Scanning Electron Microscopy and ultraviolet–visible spectroscopy while average diameter of soil particles was found to be 8.21 µm. The daily cycle of outdoor conditions has been performed on the module and it was found that after 7 daily soil cycles, the module lost 33.54% of short circuit current. In future work, same soiling station will be utilized to study effect of anti-soiling coating, economics of different cleaning processes, and the soiling loss at variable humidity, wind speed, and tilt angle.

The Daphne alpina (D. alpina) mediated silver oxide nanoparticles (Ag2O-NPs) were synthesized and loaded with moxifloxacin (MAg2O-NPs) using sonochemical process. The surface area and pore parameters were determined through Brunauer–Emmett–Teller and Barrett–Joyner–Halenda methods using N2 adsorption–desorption data. The mixed phase (cubic, tetragonal and hexagonal) synthesis of Ag2O-NPs and loading of moxifloxacin was confirmed through X-ray diffraction analysis and the average crystallite size for Ag2O-NPs and MAg2O-NPs were 38.52 and 41.03 nm respectively. The transmission and scanning electron microscopies were utilized to study surface morphology, indicate that the visible boundaries disappeared after the functionalization of Ag2O-NPs with moxifloxacin. The chemical composition of both samples was analyzed via energy dispersive X-ray and Fourier transform infrared spectroscopies. Agar well diffusion method was followed to test the Ag2O-NPs and MAg2O-NPs against selected microorganism. The bactericidal and fungicidal effects of MAg2O-NPs were significantly higher than the Ag2O-NPs.

The nano-sized zinc titanate heterojunction was synthesized via co-precipitation method and its texture parameters were studied via nitrogen adsorption/desorption method. The surface area (214 m2/g) and pore size (2.3 nm) were determined by BET and BJH methods. The phase composition and crystalline nature was investigated using X-ray diffractometer (XRD) and resulting crystallite sizes for TiO2 and ZnO were 44.0 and 70.85 nm respectively. The scanning electron and transmission electron microscopies (SEM and TEM) were operated to examine the surface morphology. The energy dispersive spectroscopy (EDX) reveals that the sample is highly pure and Fourier transform infrared (FTIR) spectroscopy was used for the chemical analysis. The synthesized zinc titanate used for the removal of Cr(VI) ions following batch method and adsorption nature was explained by applying Freundlich and Langmuir equations to batch adsorption data. The endothermic nature of the adsorption process was exposed through thermodynamic investigation and 1:1 exchange ratio was determined for hydrogen and Cr(VI) ions. The zinc titanate heterojunction was used as a photocatalyst under irradiation of simulated sun light for the degradation of Rh-6G and almost all dye was degraded with degradation arte of 1.48 × 10−2 min−1.

Dust accumulation significantly reduces the efficiency of a photovoltaic (PV) module, and the unavailability of an economical and efficient cleaning solution is the persistent problem. Therefore, the focus of this study is to investigate the effect of dust on PV performance and propose a novel cleaning system for the removal of dust from the PV modules. The outdoor experiment is conducted on the monocrystalline (mono-PV) and polycrystalline (poly-PV) PV modules. Each experimental set contains two PV modules (mono-PV and poly-PV), one set is cleaned every day and the other set left uncleaned throughout the experiment. The cleaning of the PV module is performed using pressurized water, sprayed through a flat-fan nozzle to clean the front surface. The wastewater is collected, filtered and directed back to the storage tank. The cleaning system has a water recovering capacity of 55% and a water requirement of 1.8 L per m2 of PV area. It has been analyzed and observed that the output power of the mono-PV module and poly-PV module has decreased by 16.16% and 11.54%, respectively after one month with the dust deposition density of 4.6 g/m2. The cleaning process improves the efficiency of the PV modules to 98% of it’s original value in 35 s of operation. It has been evaluated that the proposed cleaning system is cost-effective for commercial sized PV modules. Furthermore, the mono-PV module (400-watts) and poly-PV module (355-watts) should be cleaned within 85 days of dust accumulation for optimum energy usage.

The photocatalytic degradation of Rhodamine 6G dye was achieved using a Ficus elastica (F. elastic) leaf extract mediated zinc oxide-zirconium dioxide nanocatalyst (ZnO-ZrO2 NC) under stimulated solar light, resulting in a substantial increase in photocatalytic activity at the highest calcination temperature. The crystal phase and crystallite size were determined using an X-ray diffractometer (XRD), and the degree of crystallinity was observed to rise with increasing calcination temperature. Energy dispersive X-ray (EDX) was used to investigate the elemental composition and purity of ZnO-ZrO2 NC. Scanning electron microscopy (SEM) was used to investigate the surface morphology, and the morphological characteristics were altered when the calcination temperature was varied. For the ZnO-ZrO2 NC calcined at 100, 300, 600, and 900 °C, the average grain size determined from SEM images is 79.56 nm, 98.78 (2) nm, 54.86 (2) nm, and 67.43 (2) nm, respectively. Using diffuse reflectance spectroscopy (DRS) data, the optical band gap energy was calculated using a Tauc’s plot. The ZnO in ZnO-ZrO2 NC calcined at 100, 300, 600, and 900 °C had band gap energies of 3.31, 3.36, 3.38, and 3.29 eV. Similarly, ZrO2 in ZnO-ZrO2 NC calcined at 100, 300, 600, and 900 °C had band gap energies of 3.96, 3.99, 3.97, and 4.01 eV, respectively. Fourier transform infrared (FTIR) spectroscopy was used to identify the presence of various functional groups. The photocatalytic activity was also examined in relation to calcination temperature, pH, starting concentration, and catalyst dosage. Enhanced photocatalytic activity was observed at pH 11 and 15 ppm initial concentration with a catalyst dose of 25 mg. The photocatalytic activity of the sample calcined at 900 °C was the highest, with 98.94 percent of the dye mineralized in 330 min at a degradation rate of 0.01261/min.

Different nanostructured semiconducting ZnO photoanodes were prepared by Hydrothermal (HT), Co-precipitation (CoP) and Chemical Bath Deposition (CBD) methods for their use in the Dye Sensitized Solar Cells (DSSCs) in the present study. Additionally, different ZnO nanocomposites were synthesized by mixing the Carbon Nanotubes (CNTs), Graphene Oxide (GO) and their combination with the ZnO nanostructures. Scanning electron microscopy (SEM) revealed various morphologies of ZnO nanostructures and nanocomposites such as nanoflowers, nanorods, rhombohedral, cubic, and cauliflower-like nanorods, and nanorods with hexagonal symmetry. Energy Dispersive X-ray (EDX) spectra confirmed the purity of the synthesized samples. X-ray Diffraction (XRD) demonstrated the hexagonal wurtzite phase of ZnO and a minor presence of CNTs and graphene. The UV-Visible, transmittance and diffuse reflectance spectra demonstrated that the ZnO synthesized through the CBD method exhibits the highest transmittance as 70–71% in the UV-Vis range and reduced % R. Optical band gaps of the samples were determined with the help of Tauc plots. Comparison of J-V characteristics showed that the ZnO synthesized via the HT method exhibits the highest conversion efficiency of 1.45%. Comparison among pristine ZnO synthesized via CBD and ZnO nanocomposites revealed that ZnO/CNTs possesses the highest energy conversion efficiency of 1.23% with enhanced JSC of 4.49 mA/cm2.

Ruthenium-based metal complex dyes have been employed extensively in dye-sensitized solar cells (DSSCs) as photosensitizers, but the cost and toxicity of metal complexes have promoted the development of metal-free organic dyes. The present investigation deals with the synthesis of hemicyanine and Dicyanoisophorone (DCI) based dyes adopting the D-π-A strategy, and their application on sensitization of nano-crystalline ZnO electrodes by appending the carboxyl (COOH) anchoring group as a pendant on the primary skeleton of dyes. Dyes have been characterized by UV, FTIR, and NMR spectroscopic studies. Absorption maxima (λ

Tin–lead (Sn–Pb) perovskite solar cells are receiving growing interest due to their applications in tandems and lead mitigation. Nonetheless, fast crystallization and facile Sn2+ oxidation restrict their ambient fabrication, which increases fabrication costs. This Letter presents an experimental study on additive assisted growth of FA0.2MA0.8Sn0.5Pb0.5I2.4Br0.6 narrow bandgap perovskite films employing a Lewis-base molecule, caffeine (1,3,7-trimethylpurine-2,6-dione), having two carbonyl functional groups (C = O) in ambient conditions (relative humidity < ∼10%). The C = O interacts with metallic ions (Sn2+ and Pb2+) via chelation to form an acid–base adduct, slowing down the fast crystallization of FA0.2MA0.8Sn0.5Pb0.5I2.4Br0.6 perovskite films. As a result, the grain size improves resulting in better structural and optical properties. In contrast, Urbach energy values showed higher electronic disorder near the band edges even upon caffeine doping implying Sn4+ doping in an ambient environment. This work accentuates the potential of the acid–base adduction to regulate uncontrolled crystallization of Sn–Pb perovskites in the ambient environment.

The synthesis of zinc stannate nanocomposite (Zn2SnO4 NC) was carried out using an environment friendly process that included the use of Ficus carica (F. carica) leaves extract as a capping and reducing agent. X-ray diffraction (XRD) analysis was used to analyze the structural and crystallographic parameters, and the crystallite was discovered to have cubic geometry. The elemental composition of the studied Zn2SnO4 NC was investigated using energy dispersive X-ray (EDX), which revealed that it was extremely pure. The band gap (3.12 eV) was calculated through Tauc plot using diffuse reflectance (DRS) data where the functional groups were explored through Fourier transform infrared (FTIR) spectroscopy. Prior to the photocatalytic reaction, some preliminary experiments were performed, which proposed that pH 9 is suitable for the mineralization of methylene blue (MB) (10 ppm) in the presence of 20 mg of Zn2SnO4 NC and simulated solar light. The 96 % of MB was degraded in 80 min with the degradation rate of 0.038 min-1.

The NiO-ZnO nanocomposite (NiO-ZnO NC) was synthesized by ecofriendly process by using Diospyros kaki (D. kaki) extract of leaves as reducing and capping agents. X-ray diffraction (XRD) was used for examined crystallinity, cell dimensions, and crystallite size (7.6 nm). To determine the purity of sample and weight percentage, energy dispersive X-ray (EDX) is used. The surface morphology was determined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). By using Fourier transform infrared spectroscopy (FTIR), functional groups in samples were determined. By using diffuse reflectance data (DRS), band gap energy calculated via Tauc plot was 3.23 eV. The photocatalytic activity was checked against brilliant green (BG) and 4-nitrophenol (4-NP) and 92.5% and 69.7% of brilliant green (BG) and 4-nitrophenol (4-NP) were degraded with rate of degradation which were 0.0281 and 0.011 min−1.

The massive growth of vertically aligned multiwall carbon nanotubes (VA-MWCNTs) on metallic substrates has been a challenge since their early days. In this paper, we demonstrate a way of replacing conventional and expensive crystalline silicon (Si) substrates with cheaper metallic substrates such as Copper (Cu) that are of great interest because of their low cost and high thermal and electrical conductivities for various potential applications. The present work addresses several issues regarding the diffusion of the catalytic particles into the Cu surface at high temperature, which hinders the growth of CNTs through chemical vapor deposition (CVD) process. Different barrier layers such as nickel (Ni), chromium (Cr), and alumina (Al2O3) have been deposited to determine their effectiveness in improving the yield of CNTs growth by stopping this diffusion. The high quality growth of VA-MWCNTs with diameter in 20–60 nm range and the length up to several hundreds of micrometers is achieved on Cu substrates with carpet thickness up to 1 mm using Al2O3 as barrier layer. Moreover, this growth process gives a good reproducibility overcoming an issue which posed a challenge to the scientific community until today. The alignment and the quality of CNTs are characterized by SEM, EDX, TGA, XPS and Raman spectroscopy and results are compared with CNTs grown in similar conditions on Si substrates. CNT grown on Cu, under the similar conditions, have less impurities, better graphitization and lower surface oxidation. The reason for interposing diffusion barrier layer is also discussed in details. This reported progress in the growth may result in a much cheaper VA-MWCNTs production. Moreover, Cu is more suitable as substrate for thermal and various other practical applications of MWCNTs.

Solvothermal synthesis of Ni-Co-metal organic framework (MOF)/graphene nanoplatelets (GNPs) nanocomposites was done for their potential application as electrode material in energy storage devices. Addition of GNPs and metallic precursors together with 2-methylimedazole in the same autoclave reactor produced smooth-nanoflakes like Ni-Co-MOF/GNPs nanocomposites as evaluated by scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis showed the presence of GNPs where GNPs do not affect the growth of MOF crystals and Ni-Co-MOF crystalline phases remain unaffected in the composite structure. Fourier transform infrared (FTIR) spectroscopy analysis confirmed the presence of organic links forming nickel-cobalt metal cations framework. Electrochemical testing (CV, EIS and GCD) of the produced composites demonstrated that GNPs addition can enhance the charge storage performance of MOF nanocomposites. The largest cycle area and most discharge time have been shown by Ni-Co-MOF/GNP-50 composite electrode that delivered the highest specific capacity values (313Cg−1 @1Ag−1), good reversibility and low internal resistance and charge transfer resistance, owing to efficient dispersion of flower-like flaky particles and efficient interconnected paths for ion and electron transportation. Moreover, Ni-Co-MOF/GNP-50 composite exhibited good thermal stability with 28% weight loss during thermogravimetric analysis. The electrochemical evaluations performed on asymmetric supercapacitor (ASC) real device expressed a specific capacity of 136.5 Cg−1@0.5Ag−1, maximum energy density of 32.2 Whkg−1@425 Wkg−1 and maximum power density of 17000 Wkg−1@12.8 Whkg−1. Moreover, the device showed a stability performance of 92.5%@10 Ag−1 after 5000 CD cycles.

High conductivity silver pastes are usually incompatible for use with thermally sensitive devices due to their higher sintering temperatures while nanoparticle inks are costly and undergo high particle agglomeration. Effectively transparent contacts (ETCs) have been designed to increase the transmittance, reduce reflectance and overcome shadowing losses in solar cells while enhancing the overall conductivity and charge collection through the grid. In this study, reactive silver ink (RSI) is mixed with a low temperature sintering conductive silver paste (150 °C) for deposition via a microchannel approach. ETCs deposited using the resulting composite were cured at a lower temperature (100 °C) with a conductivity of the order of 103 1/Ω-cm and a transparency >90% in the visible region, promising a reduction in optical and electrical losses when compared to bare transparent conductive oxides. The use of low temperature curing conductive material makes ETCs suitable for use in thermally sensitive optoelectronic and photovoltaic devices, hence they were ultimately deposited on perovskite solar cells and the solar cell parameters were measured.

The aim of this study was to explore the antibacterial and antioxidant efficacy of nickel oxide nanoparticles (NiO NPs). The Raphanus sativus (R. sativus) extract mediated NiO NPs were calcined at 100, 300, 600 and 900 ℃ in a muffle furnace for 3 h. The increased intensity of diffraction bands in the X-ray diffraction (XRD) spectrum suggest that the degree of crystallinity increases with increasing calcination temperature. The desired elements was depicted in the energy dispersive X-rays (EDX) spectrum confirm the purity of the NiO Sample. The variation in surface morphology and increase in the particles size from 12.78 to 51.42nm was determined from the transmission electron microscope (TEM) micrographs. The shift toward higher wavelength was observed in the diffuse reflectance spectroscopy (DRS) spectra with increasing calcination temperature, results into a clear decrease in band gap from 3.12 to 2.86 eV. The presence of hydroxyl group along with other organic moieties were confirm through Fourier transform infrared (FTIR) spectroscopy analysis. The biological potential of the calcined NiO NPs was examined during the antibacterial and antioxidant experiments. The antibacterial effect of NiO NPs was studied using the agar well diffusion process, and the ABTS free radical scavenging potential of NiO NPs was also assessed. The activity of NiO NPs calcined at 100 °C is greater than that of those calcined at higher temperatures.